A storage area network (SAN) is used to attach storage devices (e.g., storage controllers, tape libraries, disk array systems, and so forth) to other computers, such as application servers, backup servers, user computers, and so forth. One widely used SAN technology is the Fibre Channel (FC) networking technology. Various types of Fibre Channel topologies can be used, including point-to-point topologies, cross-point switch (or fabric) topologies, or arbitrated loop topologies.
When a storage area network first starts up (or when the storage area network resets for whatever reason), one of the tasks performed by one or more controllers (and SAN switches) in the storage area network is the discovery of storage devices that are attached to the storage area network. In some cases, one or more malfunctioning storage devices can prevent the device discovery process from completing. For example, during a discovery procedure in a storage area network, a storage device can repeatedly send a command to re-initialize the storage area network, which would restart the device discovery procedure. After several restarts, a controller may decide to disable an entire bus in the storage area network. If all buses to a particular storage device (or multiple storage devices) are disabled (failed), then the data contained in that particular storage device (or storage devices) will not be accessible.